This invention relates to polymethoxybenzyl piperazine derivatives, processes for producing the same and blood circulation system improving agents using the same.
In recent years, great hopes have been placed on curative or preventive drugs for diseases in circulatory systems such as cerebral circulation system, coronary circulation system and the like, and in order to meet the demand, various drugs have been made fit for practical use. However, such drugs often require administration for a long period of time, and there is desired a drug which is safe and has excellent effect at a smaller dose.
The present inventors has noted that trimetazidine, a coronary vasodilator, has an effect of stabilizing myocardium, almost completely prevents actions of factors causing angina pectoris on myocardium, and hence contributes to stabilization of myocardial actions. In addition, the present inventors have judged that the duration in blood of trimetazidine administered is not so long, so that no desired drug efficacy is obtained. In order to obtain the desired drug by improving the defects of trimetazidine without losing its properties, the present inventors have devoted themselves to study while investigating the correlation between chemical structure and drug efficacy and have consequently accomplished this invention.
On the other hand, U.S. Patent No. 4,100,285 discloses N-substituted trialkoxybenzyl piperazine derivatives, but they are rather high in toxicity, and too large in lowering in the heart rate and hence not satisfactory.